Usual technique

The usual practice of creating a dotted line (usually for either leading up to a page number in a table of contents OR preparing a space for users to add information to a handwritten form) is often accomplished by the tabs feature. For example:

This is achieved by making
a paragraph style that has a tab stop that has been right-aligned to the end of
the text frame, and in the leader text field of the tab dialog box, a period
has been entered, and it is this period that repeats to generate the dotted
line.

Issues with this technique

My preferred technique

Instead, I prefer to make a character style called “dotted line” giving it the dotted line appearance that I’m after in the underline panel of the character style dialog box.

If more control is
required, I can also prepare a stroke style specifying the dot style and
frequency that the dots appear.

I can then either
apply the character style manually to the areas requiring the dotted lines, or
I can make a paragraph style that calls the dotted line character style using a
GREP style that looks for tab spaces.

Bonus tip

Note that my GREP style is looking for \t|~y rather than just \t – the ~y represents a right indent tab. For dot leaders that need to go to text at the end of a text-frame, I prefer to use a right indent tab instead of setting a right align tab, because if the text frame changes width and I want the right aligned item to remain right aligned to the text frame, I don’t have to adjust the tab stop of the right align tab.

To insert a right indent tab, press SHIFT+TAB. This will work anywhere in a text frame except within a table where it will highlight the previous cell. To apply a right indent tab inside a table, either insert one via right-clicking to call upon the contextual menu, then navigate to Insert Special Characters, Other, then Right Indent Tab.

Otherwise, it can be called upon by opening the quick-apply menu via COMMAND+RETURN on Mac (or CONTROL+RETURN on Windows) and type either Right Indent Tab (or, if you’re really lazy – nt tab as highlighted in pink in the figure below).